fix for Cannot call method 'getTime' of null

Fixed this error, when I had some unfinished jobs due errors in filesystem 
/opt/node-0.10.21/lib/node_modules/strider/node_modules/mongoose/lib/utils.js:419
        throw err;
              ^
TypeError: Cannot call method 'getTime' of null
    at Promise.<anonymous> (/opt/node-0.10.21/lib/node_modules/strider/lib/backchannel.js:158:61)